Method of handling chipper knives



May 17, 1949. I I PAYZER 2,470,262

METHOD OF HANDLING CHIPPER KNIVES Original Fil ed Oct. 9, 1944 Patented May 17, 1949 STATES METHGD oramount; CHIPPER-K'NIVES Stanley'D. Payzer,

Murray Manufacturing corporation of W1SO0I1S1I1- Original application-October. 9,v 1944, Serial No. 557,808. Dividedtand this application August 27, 1945, SeriaLNo. 612,740

1 Claim; 1

My invention relates generallyto improvements in'the art of handling wood chipper knives, and relates'm'ore specifically to an improved method of expediting insertion and-removal of the cutting blades "of rotary 'wood chippers relative to their carrier rotors or discs.

Rotary wood chippers each comprising-a rapidly revolvable disc provided with an annular'series of radially disposed knives having cutting edges protruding from'one'side face of the disc and cooperating with a hopper for feeding logs or wood slabs -at-'a-"downward inclination toward said disc face openings, and can be dislodged only with great efiort; and the time consumed and wastedby the prior tedious methods of manually inserting and removing. such knife blades has. always been a source .of annoyanceand expens -to the operators. accessible for insertion and removal rat the zone of .the feed hopper, free access tothe cutting blades maybe-had on the side of the rotor axis opposite to the hopper; and although this available space remote from the hopper has heretofore.

been: used for inserting and removing the-knives, it previously wasnecessary to also remove various other parts of the rotor assemblages in order to apply or withdraw. the cutting blades, thereby making. these operations bothdifiicult anddangerous.

Itis therefore an object of my present invention t rprovide an improved method cit effecting insertion and removal of the knives of'rotary chippers blades, from and to their: carrier discs, without necessitating complete removal of the normal knife:retainin selements;of the rotor assemblage. A further'objectof this invention is to provide 'aasimplez'andieifctive .methodzcf quickly dislodgings'and removing chipper knife blades, andior.

While the chipper knives arenot readily 3 Wausau, Wis., assignortoD. J.

00., Wausau, Wis., a

2 safely manipulating the cutting memberszduring insertion and removal thereof.

Still another object of my invention is to provide-an improved method: of safely andsexpedi tiously handling chipper knives or the like,:-:so:as to reduce to a minimum the dangerand; the :time lost in reconditioning or renewingsuch knives;

These and other objects and. advantages: of "the invention will be apparent from the following.:detailed description; and the present applicationis a division of applicationeSerialNumber 557,808,

filed October 9, 1944;

A clear conception of the several steps involved in myimproved method of handling" chipper knives, and of the construction and operation. of

one type of apparatus which may housed in commercial exploitation of the method, may behad byreferring to th drawing accompanying and forming a part of this specification wherein like reference characters designate the sameor similar parts in the various views.

Fig. 1 isa relatively. large fragmentary;scction:through a chipper rotor taken across-one of theknife or blade assemblages, and showingvsa knife blade being forced upwardly-outof its normal retaining slot and engagedby a suspension clamp or tongs;

Fig. 2.is a somewhat reduced side elevation of a chipper knife engaged by and suspended from .one of .the improved handling tongs;v and Fig. 3 is a further reduced diagrammaticside view of a typical rotary chipper disc showingthe approximatenormal disposition of the radiating knives, and the relative position of the feeding hopper orspout.

While the invention has been shown and: described herein as being especially useful in: conjunction with chipper knife assemblageswofa particular type, it is in fact more generally applicable and it is not my desire or intent-tonnnecessarily restrict the scope or utility of the improvement by'virtue of this speicfic disclosure.

Referring to the drawing, the'rotary chipper and knife assemblage specifically shown, comprises in generala chipper'rotor or'rotary*-'disc 5 mounted for rapid 'rotation'upon :a central shaft 6 :andhaving. an annular-series of elongatedapproximately radial through openings or :slotsl therein, a chipper blade or knife 8 disposed within. each of the. disc openings l;-and.each havingawsharpcutting edge 1 9 protruding beyondone side. face [0* of the; disc; 5; a :long or; s1ah:.:feed hopperrhaving a downwardlyyinclinedrdelivzery spout l rdircctedatoward .the disc face-J0: cache 1 side of the'axiszofsthesrotor :shaftfi; a wedgegloc'k bar I2 normally coacting with each knife blade 8 Within its confining slot 1 to clamp the adjoining knife in operative position; an elongated holding member or plate I3 firmly attached to the other rotor disc face I4 adjacent to each slot I and wedge bar I2, by means of cap screws I5; a number of adjusting screws, not shown, normally coacting with each plate I3 and with the blunt rear end of the adjacent blade 8; and a number of locking screws I6 coacting with each wedge bar I2 and with the adjacent holding plat I3 to firmly clamp the adjacent blade 8 in cutting position.

The rotor discs 5 may be of any desirable diameter and may be provided with any suitable number of slots 7 and knives 8, and these knife carrier discs are normally rotatable at high speed in the direction of the arrow shown in Fig. 3, so as to rapidly revolve the successive knife blades 8 past the feed spout discharge opening. The blades or knives 8 are constructed of durable metal, but because of the heavy duty which these cutting blades perform, they must be frequently removed for regrinding of the cutting edges 9, or for renewal after repeated sharpening. As clearly indicated in Fig. 3, the successive knives 8 are not readily accessible at the zone of the feed spout II unless this spout is removed with considerable diiiiculty, but the blades are freely accessible at all times at the opposite side of the rotor shaft 6, remote from this feed spout I I. During normal operation of the chipper, the knife blades 8 are clamped firmly against the inclined bounding surfaces Il of the rotor slots I by the adjacent Wedge bars I2 and locking screws I 6, and these screws must be released in order to loosen the knives and to permit them to be withdrawn from their confining openings or slots.

In accordance with prior practice, it was customary to release the blade locking wedges, whenever a knife blade was to be removed, and to thereafter either utilize slow acting jack screws applied to the rear blunt end of the blade to lift it forwardly part way out of its confining slot, or to remove the blade holding plate so as to permit the knife to be withdrawn rearwardly from within its confining opening. Both of these methods were extremely tedious, and consumed a great deal of time, and they were also exceedingly dangerous when heavy blades or knives were being handled in connection with larger units.

In accordance with my present improved method, removal and insertion of the knife blades 8 is greatly facilitated and expedited, by providing each of the opposite ends of each blade 8 with a series of alined detents I8, and by also providing the opposite ends of each holding plate I3 with alined sockets I9, see Figs. 1 and 3. The reason for providing several sets of alined detents I8 in each blade 8, is to make the successive sets available as the blade is ground down during resharpening thereof. I additionally provide each elongated plate l3 with several parallel holes 20, which may be internally threaded and normally used for the reception of the blade adjusting screws not shown; and when it becomes desirable to remove a knife 8, the blade which is to be withdrawn should be positioned to the left of the central shaft axis and pointing upwardly as shown in Figs. 3 and 1 respectively.

After releasing the wedge bar I2 by loosening the locking screws I6 thereof, I apply to the pivot sockets IS, a U-shaped yoke or jack carrier 2 I having adjustable pivot pins 22 screw threaded .4 into the arms of the yoke and adapted to swingably coact with the alined sockets I9. A transverse bar 23 having parallel pins 24 which are slidably cooperable with the holes 20 of the adjacent plate I3 and which are adapted to contact the lower blunt end of the corresponding blade 8, is then positioned between the side arms of the yoke 2|, and a hydraulic jack 25 is disposed centrally between the bar 23 and the lower parallel cross-bar of the U-shaped carrier 2|, see Figs. 1 and 3. The hydraulic jack 25 may be of any conventional type, comprising a cylinder 26 having an oil supply reservoir therein and a base 21 firmly attached to the carrier 2| as by welding, a plunger 28 slidable within the cylinder 2B and adapted to engage the transverse bar 23, a small manually operable pump 29 carried by the base 21 and being operable to force liquid from the supply reservoir to the displacement chamber beneath the plunger 28, and a by-pass valve 30 for permitting free return of the liquid from the displacement chamber to the supply reservoir whenever the plunger 28 is being lowered. It will be apparent, that by operating the jack 25 so as to elevate the plunger 28 thereof after the screws I6 have been loosened, the corresponding knife blade 3 may be forcibly lifted or elevated as illustrated in Fig. 1 so as to cause its sharpened or cutting edge 9 to move outwardly beyond the disc surface I8 any desired distance.

In order to further facilitate exploitation of the method, I also provide an improved blade clamping and handling tongs 3| such as shown in Figs. 1 and 2, for the purpose of effecting safe withdrawal of the loosened blades 8, and reinsertion thereof within the openings 1 of the rotor 5. These tongs 3| consist of a pair of similar hook elements 32 pivotally interconnected by means of a central pivot pin 33 and having their lower ends provided with points 34 adapted to engage the several sets of alined notches or detents I 8 formed in the blades 8, while their upper ends are connected by swingable links 35 with a suspension ring 36 which is adapted to coact with the hook of an ordinary overhead crane in an obvious manner. When the hook elements 32 are applied to a knife 8 as illustrated, and pulling or lifting force is applied to the ring 36, the points 34 will be driven into the detents I8 and the blade 8 will be firmly and safely suspended, but as an additional precaution, I may also provide a locking latch 31 swingably mounted upon one of the elements 32 by means of a pivot 38 and cooperable with a pin 39 on the other, in order to positively lock the blade 8 within the tongs 3|, see Fig. 3.

While the mode of utilizing the relatively simple apparatus during the commercial exploitation of my improved method, should be quite clearly apparent from the foregoing detailed description, a short rsum of my improved system of removing and inserting chipper blades, will be given. When it becomes desirable to remove a knife 8 for regrinding or replacement, the worn knife blade should be positioned as shown in Fig. 3 on the side of the shaft 6 remote from the feed spout II, whereupon the blade adjusting screws should be removed from the holes 20 if no special holes have been provided, and the adjustin screws IB should be loosened so as to release the wedge bar I2. The yoke 2| having the jack 25 secured thereto should then be suspended by means of the pivot pins 22 from the sockets IQ of the holding plate I3, and the cross-bar 23 with its parallel pins 24 should be applied to the holes 20 in the plate Hi. The yoke 2i and jack 25 may then be swung into alinement with the bar 23 and pins 24, after which the pump 29 may be operated to cause the plunger 28 to move upwardly within the jack cylinder 26 and to raise the cross-bar 23 and the pins 2 Continued operation of the jack 25 will cause the pins 24 to force the knife blade 8 upwardly and to simultaneously slightly elevate the wedge bar l2 so as to free the blade 8 from lateral clamping pressure. As the blade 8 becomes elevated sufficiently so as to expose the uppermost set of detents 13 therein, the clamping tongs 3! may be applied to these exposed detents or notches, and the blade 8 may thereafter be freely lifted from within the confining slot of the opening 7 with the aid of a crane applied to the ring 36. After the blade has been resharpened and is ready for reinsertio-n within the rotor 5, or in case a new blade 8 is to be inserted, the blade may again be brought into approximate position relative to the rotor 5 and it may be swung about the holding points 34 of the clamping tongs 3| so as to cause the lower blade end to enter the slot between the wedge block 12 and the rotor surface ll. Continued lowering of the blade will then cause it to slide into proper position, it being necessary of course to first lower the pins 24 with the aid of the by-pass valve 30 of the jack 25. The yoke 2| together with the jack 25, and the bar 23 together with its pins 24 may then be removed and the blade 8 may be subsequently again firmly clamped within the rotor 5 after it has been properly located with its cutting edge 9 protruding from the side surface l9 of the rotor. In this manner, the knife blades 8 of the rotor 5 may be quickly and safely removed or inserted, with minimum loss of time and without danger of injuring the operator. As the blades 8 become worn and are reground, the successive side detents I3 will become effective for removal and insertion of the blades until they are sufficiently worn so as to make them unsatisfactory for further use.

From the foregoing detailed description of my improved method of handling chipper blades or knives, it will be apparent that the present invention does in fact provide a system for safely and effectively removing and inserting these blades. The several successive steps in the new method can be quickly and expeditiously performed with the aid of relatively simple and inexpensive mechanism, thereby preventing excessive loss of time in reconditioning or renewing the knives 8, and at the same time insuring utmost safety in the handling of the relatively sharp and heavy blades. With the aid of my improved method of handling chipper blades, it is unnecessary to completely remove the normal blade clamping mechanisms, and it is also unnecessary to undesirably modify standard blade holding assemblages and knife blades. The improved apparatus is adapted to be quickly applied and removed, and the handling tongs 3| may either be manipulated by hand or with the aid of an ordinary crane so as to expedite the removal and reinsertion of the cutting blades 8 without disturbing the feed hopper spout l l of the chipper. While the present improvement is especially and advantageously applicable to chipper knife assemblies of a particular type, it is also more enerally applicable to other standard chippers and blade holding assemblies.

It should be understood that it is not desired to limit this invention to the precise steps of the method, herein described, for various modifications within the scope of the appended claim may occur to persons skilled in the art.

I claim:

The method of removing a knife blade provided with opposite end detents and an intervening cutting edge from a chipper rotor revolvable about a horizontal axis and having a radial opening within which the knife is normally confined in an inclined position by a wedge bar disposed within the opening and a holding plate coacting with the bar and having opposite end sockets and transverse guide holes extending therethrough parallel to the blade, which method comprises, revolving the rotor to upwardly incline the blade with its cutting edge uppermost and releasing the wedge bar, slidably inserting pins within the guide holes and applying uniform pressure to the lower blunt end of the blade through the pins to partially eject the upper sharp blade end from within the rotor opening, and thereafter applying an upward pull to the blade detents to finally withdraw the blade bodily from within the rotor.

STANLEY D. PAYZER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,026,548 Allien May 14, 1912 1,376,414 Farnsworth May 3, 1921 1,454,088 Thrift May 8, 1923 1,488,020 Malone Mar. 25, 1924 1,500,903 Shipley July 8, 1924 1,899,351 Overfelt Feb. 28, 1933 2,084,439 Hamer June 22, 1937 2,113,598 Mueller Apr. 12, 1938 2,134,749 Burt Nov. 3, 1938 2,153,035 Burt Apr. 4, 1939 2,345,391 Grossett Mar. 28, 1944 2,348,293 I-Iamer May 9, 1944 2,388,799 Payzer Nov. 13, 1945 2,409,463 Ahrndt Oct. 15, 1946 

